1. Field of the Invention
The present invention relates to the installation of lines and, more particularly, to a method an apparatus for projecting a line through a conduit or between panels or walls of an existing structure.
2. Description of the Prior Art
It is well known to pass a line in a conduit by attaching the leading end of the line to a projectile which is forced through the conduit by fluid pressure. Typically, the entry end of the conduit is sealed by a plug so that fluid pressure could be built up therein to propel the pulling projectile.
For instance, U.S. Pat. No. 4,840,352 issued on Jun. 20, 1989, to Ellis and U.S. Pat. No. 4,848,734 issued on Jul. 18, 1989, to Ford both disclose a radially expandable plug with a line passage and a fluid passage extending therethrough so that a pulling projectile can be propelled by fluid pressure through the conduit to pull a line through the plug and into the conduit.
Although the plugs described in the above mentioned patents are effective, it has been found that there is a need for a new plug which can be used for sealing a wide variety of conduits, while being lightweight and of simple construction.
In the past, as disclosed in U.S. Pat. No. 2,515,953 issued on Jul. 18, 1950 to Dufresne, it has also been proposed to use flexible tubing to facilitate access to difficult to reach conduits. However, known flexible tubes used for conveying fluid do not exhibit sufficient flexibility to allow important change of direction over small distances.
Accordingly, there is a need for an improved line projecting apparatus which is adapted to provide access to difficult to reach conduits, such as those located in constricted area.